Remember fnspec EAF flags in modref summary

Jan Hubicka hubicka@kam.mff.cuni.cz
Sat Nov 13 14:21:49 GMT 2021


Hi,
this patch stores eaf flags from fnspec to modref summaries.  THis makes
them survive signature changes and also improves IPA propagation in case
modref is not able to autodetect given flag.

Bootstrapped/regtested x86_64-linux, comitted.

Honza

gcc/ChangeLog:

	* attr-fnspec.h (attr_fnspec::arg_eaf_flags): Break out from ...
	* gimple.c (gimple_call_arg_flags): ... here.
	* ipa-modref.c (analyze_parms): Record flags known from fnspec.
	(modref_merge_call_site_flags): Use arg_eaf_flags.

diff --git a/gcc/attr-fnspec.h b/gcc/attr-fnspec.h
index 1154c30e7b0..cd618cb342b 100644
--- a/gcc/attr-fnspec.h
+++ b/gcc/attr-fnspec.h
@@ -264,6 +264,29 @@ public:
     return str[1] == 'C' || str[1] == 'P';
   }
 
+  /* Return EAF flags for arg I.  */
+  int
+  arg_eaf_flags (unsigned int i)
+  {
+    int flags = 0;
+
+    if (!arg_specified_p (i))
+      ;
+    else if (!arg_used_p (i))
+      flags = EAF_UNUSED;
+    else
+      {
+	if (arg_direct_p (i))
+	  flags |= EAF_NO_INDIRECT_READ | EAF_NO_INDIRECT_ESCAPE
+		   | EAF_NOT_RETURNED_INDIRECTLY | EAF_NO_INDIRECT_CLOBBER;
+	if (arg_noescape_p (i))
+	  flags |= EAF_NO_DIRECT_ESCAPE | EAF_NO_INDIRECT_ESCAPE;
+	if (arg_readonly_p (i))
+	  flags |= EAF_NO_DIRECT_CLOBBER | EAF_NO_INDIRECT_CLOBBER;
+      }
+    return flags;
+  }
+
   /* Check validity of the string.  */
   void verify ();
 
diff --git a/gcc/gimple.c b/gcc/gimple.c
index 1e0fad92e15..037c6e4c827 100644
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -1567,22 +1567,7 @@ gimple_call_arg_flags (const gcall *stmt, unsigned arg)
   int flags = 0;
 
   if (fnspec.known_p ())
-    {
-      if (!fnspec.arg_specified_p (arg))
-	;
-      else if (!fnspec.arg_used_p (arg))
-	flags = EAF_UNUSED;
-      else
-	{
-	  if (fnspec.arg_direct_p (arg))
-	    flags |= EAF_NO_INDIRECT_READ | EAF_NO_INDIRECT_ESCAPE
-		     | EAF_NOT_RETURNED_INDIRECTLY | EAF_NO_INDIRECT_CLOBBER;
-	  if (fnspec.arg_noescape_p (arg))
-	    flags |= EAF_NO_DIRECT_ESCAPE | EAF_NO_INDIRECT_ESCAPE;
-	  if (fnspec.arg_readonly_p (arg))
-	    flags |= EAF_NO_DIRECT_CLOBBER | EAF_NO_INDIRECT_CLOBBER;
-	}
-    }
+    flags = fnspec.arg_eaf_flags (arg);
   tree callee = gimple_call_fndecl (stmt);
   if (callee)
     {
diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c
index 90985cc1326..669dbe45a3d 100644
--- a/gcc/ipa-modref.c
+++ b/gcc/ipa-modref.c
@@ -2476,6 +2476,14 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto,
   /* Do the dataflow.  */
   eaf_analysis.propagate ();
 
+  tree attr = lookup_attribute ("fn spec",
+				TYPE_ATTRIBUTES
+				  (TREE_TYPE (current_function_decl)));
+  attr_fnspec fnspec (attr
+		      ? TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr)))
+		      : "");
+
+
   /* Store results to summaries.  */
   for (tree parm = DECL_ARGUMENTS (current_function_decl); parm; parm_index++,
        parm = TREE_CHAIN (parm))
@@ -2502,6 +2510,18 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto,
 	  continue;
 	}
       int flags = eaf_analysis.get_ssa_name_flags (name);
+      int attr_flags = fnspec.arg_eaf_flags (parm_index);
+
+      if (dump_file && (flags | attr_flags) != flags && !(flags & EAF_UNUSED))
+	{
+	  fprintf (dump_file,
+		   "  Flags for param %i combined with fnspec flags:",
+		   (int)parm_index);
+	  dump_eaf_flags (dump_file, attr_flags, false);
+	  fprintf (dump_file, " determined: ");
+	  dump_eaf_flags (dump_file, flags, true);
+	}
+      flags |= attr_flags;
 
       /* Eliminate useless flags so we do not end up storing unnecessary
 	 summaries.  */
@@ -2522,8 +2542,8 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto,
 		       "  Flags for param %i combined with IPA pass:",
 		       (int)parm_index);
 	      dump_eaf_flags (dump_file, past, false);
-	      fprintf (dump_file, " local ");
-	      dump_eaf_flags (dump_file, flags | past, true);
+	      fprintf (dump_file, " determined: ");
+	      dump_eaf_flags (dump_file, flags, true);
 	    }
 	  if (!(flags & EAF_UNUSED))
 	    flags |= past;
@@ -2561,7 +2581,7 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto,
 	  fprintf (dump_file,
 		   "  Retslot flags combined with IPA pass:");
 	  dump_eaf_flags (dump_file, past, false);
-	  fprintf (dump_file, " local ");
+	  fprintf (dump_file, " determined: ");
 	  dump_eaf_flags (dump_file, flags, true);
 	}
       if (!(flags & EAF_UNUSED))
@@ -2591,7 +2611,7 @@ analyze_parms (modref_summary *summary, modref_summary_lto *summary_lto,
 	  fprintf (dump_file,
 		   "  Static chain flags combined with IPA pass:");
 	  dump_eaf_flags (dump_file, past, false);
-	  fprintf (dump_file, " local ");
+	  fprintf (dump_file, " determined: ");
 	  dump_eaf_flags (dump_file, flags, true);
 	}
       if (!(flags & EAF_UNUSED))
@@ -4503,27 +4523,7 @@ modref_merge_call_site_flags (escape_summary *sum,
       if (fnspec_sum)
 	{
 	  attr_fnspec fnspec (fnspec_sum->fnspec);
-	  int fnspec_flags = 0;
-
-	  if (fnspec.arg_specified_p (ee->arg))
-	    {
-	      if (!fnspec.arg_used_p (ee->arg))
-		fnspec_flags = EAF_UNUSED;
-	      else
-		{
-		  if (fnspec.arg_direct_p (ee->arg))
-		    fnspec_flags |= EAF_NO_INDIRECT_READ
-			     | EAF_NO_INDIRECT_ESCAPE
-			     | EAF_NOT_RETURNED_INDIRECTLY
-			     | EAF_NO_INDIRECT_CLOBBER;
-		  if (fnspec.arg_noescape_p (ee->arg))
-		    fnspec_flags |= EAF_NO_DIRECT_ESCAPE
-				    | EAF_NO_INDIRECT_ESCAPE;
-		  if (fnspec.arg_readonly_p (ee->arg))
-		    flags |= EAF_NO_DIRECT_CLOBBER | EAF_NO_INDIRECT_CLOBBER;
-		}
-	    }
-	  implicit_flags |= fnspec_flags;
+	  implicit_flags |= fnspec.arg_eaf_flags (ee->arg);
 	}
       if (!ee->direct)
 	implicit_flags = deref_flags (implicit_flags, ignore_stores);


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